What is corneal edema?
Corneal edema is an accumulation of water in the cornea. This leads to an increase in the thickness of the cornea and swelling. Corneal edema can be caused by various diseases, including Fuchs endothelial dystrophy.
Symptoms include pain worsened by the blinking of the eyelid and the feeling of a foreign body in the eye. Depending on the cause of the corneal edema, there are various treatment options available. Corneal edema can cause symptoms of varying severity depending on the severity of the symptoms.
In most cases, one of the central symptoms is sensitivity to light and glare, as the eye is in an increased state of irritation. As a result, the eye reacts more strongly to various external stimuli. This is often accompanied by eyelid cramps.
In addition, corneal edema is very often associated with severe pain. There are many nerve endings at the cornea, which means that the cornea is well supplied with nerves. When the cornea is irritated, this signal is accordingly received and transmitted by a great many nerves, which is why there is usually severe pain.
These are usually aggravated by the blinking of the eyelid, as this creates mechanical pressure on the already irritated and thickened cornea. Furthermore, the affected persons often have the feeling of having a foreign body in their eye, since the pathological water retention leads to an increase in corneal mass. In many cases, corneal edema also leads to a decrease in vision.
The cornea is an important part of the eye for sharp vision. Due to a swelling, this function can no longer be performed and the affected persons have reduced vision. The diagnosis of corneal edema is often made by clinical examination.
Depending on the extent, the corneal edema may already be visible to the naked eye. In many cases, additional examination instruments can help with the diagnosis. For example, in the case of causative glaucoma, the intraocular pressure should be measured.
On the other hand, a more precise inspection of the cornea using a slit lamp, i.e. a special magnifying microscope, can be helpful. To treat corneal edema, so-called dehydrating eye drops can be used. This can be, for example, table salt in a certain concentration.
The electrolytes in the eye drops cause the water to flow back behind the cornea, where it can be removed like the rest of the aqueous humor and enter the circulation. Acute corneal edema can cause damage to the cornea with tears. In this case a keratoplasty, i.e. a corneal transplantation, may be necessary.
When treating corneal edema, the therapy of the underlying cause is very important. For example, if there is an infection of the cornea, it can be treated with antibiotic, antiviral or antifungal eye drops, i.e. against bacteria, viruses or fungi. If corneal edema occurs shortly after cataract surgery, an ophthalmologist should be consulted to investigate possible complications of the operation.
In the case of an acute glaucoma attack, it should be treated as soon as possible, as the eye and thus also the vision can be permanently damaged. In the case of corneal edema, various eye drops can help. These include so-called dehydrating eye drops.
These ensure that the stored water drains out of the swollen corneal tissue. These eye drops are often used in cases of underlying Fuchs endothelial dystrophy, for example. For acute pain, pain-relieving eye drops and medication should also be used.
Unfortunately, the corneal edema is often so far advanced that treatment with medication alone is not sufficient. During cataract surgery, i.e. the use of a new lens when it becomes cloudy, corneal edema may occur in some cases in the course of the postoperative period. During the surgical treatment, various structures of the eye, including the cornea, are opened and thus irritated.
This can promote water retention in the corneal tissue. An additional risk factor is a Fuchs endothelial dystrophy that already exists before the operation. If pain and swelling are noticed after cataract surgery, an ophthalmologist should be consulted as soon as possible.Learn everything about cataracts.
A corneal edema can have various causes. Common to all of them is an increased accumulation of water in the so-called stroma, the structure-giving tissue, the cornea. This reduces the transparency or permeability of the cornea.
Various irritations and damages of the cornea can lead to corneal edema. These include keratitis, as the inflammation of the cornea, which is usually caused by bacteria such as staphylococci or streptococci. In rare cases, fungi, such as aspergillus, or viruses, such as herpes simplex, can also lead to corneal inflammation.
Acute glaucoma, i.e. a glaucoma attack, can also lead to corneal edema. This leads to an excessive accumulation of aqueous humor in the front part of the eye. This leads to an acute increase in intraocular pressure, which can cause water to accumulate in the cornea.
The so-called Fuchs endothelial dystrophy can also lead to corneal edema. Due to a congenital disease of the lowest corneal layer (endothelium), the permeability of the cornea is increased, which allows water to increasingly accumulate in the corneal tissue. A rare cause nowadays is the incorrect use of contact lenses.
If worn for too long, the cornea may become undersupplied with oxygen (hypoxia), which promotes water retention. The duration of corneal edema depends on the origin and extent of the swelling. In the case of an acute inflammation, which leads to a rapid storage of water in the corneal tissue, a quick therapy must also be carried out.
In this case, corneal edema usually lasts from a few days to weeks. However, if it is a chronic or degenerative disease, the duration can be weeks to months or even years. In a Fuchs endothelial dystrophy, for example, water retention occurs due to a malfunction of a corneal layer, which increases in size as the disease progresses and is therefore a gradual process.
